file_push · React Native MCP: Risk & Policy

WHAT IT DOES

What file_push does on React Native

AI agents use file_push to create or update resources in React Native — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your React Native environment.

WHY IT NEEDS A POLICY

Why file_push needs a policy

This tool creates or modifies files on a mobile device, which is a reversible write operation. While it could potentially overwrite existing files (making it somewhat destructive), the primary purpose is file transfer/creation rather than deletion.

From the tool's definition Tool name 'file_push' and description 'Push local file to device' indicates the tool writes/transfers files to a mobile device.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

file_push Rate-limited

file_push stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "file_push": {
      "limits": [
        {
          "counter": "file_push_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches React Native, so you can run agents against it safely.

FAQ

Questions about file_push

What does the file_push tool do? +

Push local file to device. iOS requires bundleId. It is categorised as a Write tool in the React Native MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on file_push? +

Register the React Native MCP server in PolicyLayer and add a rule for file_push: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches React Native. Nothing to install.

What risk level is file_push? +

file_push is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit file_push? +

Yes. Add a rate_limit block to the file_push rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block file_push completely? +

Set action: deny in the PolicyLayer policy for file_push. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides file_push? +

file_push is provided by the React Native MCP server (@ohah/react-native-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.